Apparatus for separating and grading ores



E L CRAIG APPARATUS FOR SEPARATING AND GRADING DEBS.

No. 443,901. PatentedDec, 30,1890;

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UNITED STATES ATENT FFICE.

EDlYARD L. CRAIG, OF SAN FRANCISCO, CALIFORNIA. I

APPARATUS FOR SEPARATING AND GRADING ORES.

SPECIFICATION forming part of Letters Patent No. 443,901, dated December 30, 1890.

Application filed July 5, 1890- Serial No, 357,713. (No model.)

To all whom it may concern.-

Be it known that I, EDWARD L. CRAIG, a citizen of the United States, residing in the city and county of San Francisco, and State of California, have invented certain new and useful Improvements in Apparatus for Separating and Grading Ores; and I do hereby declare that the following is a full, clear, and exact description of the same.

This invention relates to machines for classifying and grading crushed or pulverized ore previous to concentration. One of the chief difficulties in concentrating gold and silver ores is due to the want of uniformity in either the size or weight of the particle composing the mass of crushed ore. Particles of a given size or weight require a given stream or currentof water and a given grade or inclination of the concentrator to effect a separation of the valuable part from the waste or gangue. If, then, the mass is subjected to a current and grade suitable for only a part of it, there results either incomplete separation of that which is saved or a great waste of values with the gangue, and in most instances both of these results occur.

In dry concentration the same difficulty exists, due to the same causes and leading to the same results. It is practically found necessary in successful concentration that the crushed ore be sized or graded, and in dry concentrating the means heretofore used have been wire-screens, which quickly become clogged and useless, especially in the finer sizes or meshes. Even screens of such mesh as keep reasonably clear separate the mass very imperfectly into parts by actual size without reference to the specific gravity of the particles, and the difiiculty of concentration is only partly removed.

By the use of my device all the particles of the mass are subjected to the action of a column of air moving horizontally in a closed space, and each particle is deposited on the bottom in such a compartment as its own weight enables it to reach, and as the specific gravity of the precious metals and the sulphurets containing them differs from that of the quartz or gangue it results that the classification of the mass is by gravity instead of size. That difference is very important in the process of concentration, as the large surface of the particles of the gangue when exposed to the action of either a stream of Water or a current of air of given strength causes it to be moved with greater facility and certainty than could otherwise be done, and it is thus gotten rid of, While the smaller surface of the metallic particles relieves it proportionately from the influence of the current, and it is hence more easily saved.

\Vhile the device has a tendency to produce concentration by its direct action, yet this is imperfect and only incidental to its main purpose-21 6., preparing the ore for successful, economical, and complete concentration.

The machine consists, essentially, of a long narrow closed passage divided by vertical partitions into open-topped chambers and having at one end a feeding-hopperfor supplying the crushed ore, and an inlet for a direct horizontal air-blast blown through the passage directly above the compartments. The crushed ore falling from the hopper is struck by the blast and carried through the passage above the chambers, the particles of ore falling successively into the compartments, the heavier particles dropping nearest the inlet end, and the others of less weight being carried along the passage to the proper points, where their gravity overcomes the force of the blast. This results in filling the compartments with ore regularly graded and of constantly-decreasing size and weight, while the dust is carried by the blast to the end of the passage or into dust-chambers beyond and communicating with it.

For a full comprehension of my invention reference mustbe made to the accompanying drawings, in which I'igure 1 is a horizontal section on the line 00 m. Fig. 2 is a vertical longitudinal section. Fig. 3 is a cross-section on the line y y. Fig. at is a detail view of one of the air-jets of the counter-blast.

It should be noted that for convenience I have herein termed the machine a separator, or alluded to a separating-passage, although it is not technically an ore-separator. Inasmuch, however, as the. ore is separated or divided according to its specific gravity the term may in view of this explanation be used without conveying an erroneous meaning. In

2o ing is provided with a wire other words, I use the term separating and grading as synonymous.

A represents the main separating-passage, which is a long closed box of regularly-in- 5 creasing width from the inlet end to the exit end. At the top of the separating-passage and at the inlet end is the feed-hopper B, provided with an ordinary sliding gate for causing the supply of ore to assume the form to of a thin sheet, and thus make a better exposure to the blast.

C is an air box or chambercommunicating with the separating-passage and having an automatic pressure-gage c. Entering the airbox is a blast-pipe D, connected to a rotary or with a perforated plate, and distribute the blast as rator.

Vithin the separator and resting upon its bottom is a series of vertical partitions (Z. ex-

tending from side to side and dividing the passage into open-topped chambers (2. These partitions, as shown in Fig. 2, are of decreasing height from the inlet end, but of increased distance apart, the object of this, as

well as of the increased width of thepassage toward the exit end, being to diminish the force of the blast as the material affected by it becomes lighter. Any number of such chambers may be used, according to the size of the machine. Within these chambers are vertical air-pipes f, supplied with air by a separate blast-pipe G, connected to the pipes f by T-cou plin gs g and pipes 71. The blast-pipe G may extend into the air-box Oand there receive a portion of the blast from the main blower, or it may receive its supply from some independent source. A detail view of the air-jet pipes f is found in Fig. 4:, from which it will be seen that each pipe is provided with a deflecting cone or spreader 2', adjustable in a cross-piecej within the pipe. In the bottom of each chamber 6 is an opening for drawing oft the ore, which is of course closed by a plug 0; otherwise during the process of separation.

The discharge end of the separator communicates with a connected series of dustchambers H, into which any dust or very 5 5 light material which has failed to settle is carried and collected.

In the operation of the separator the crushed ore fed from the hopper is encountcred at once by the divided air-blast entering through the screen. The heavier particles fall at once into the collecting-chambers near the inlet end, and in falling are met by the blast from the pipe G, which permeates the mass and drives the lighter matter upward. As the weight of the particles of ore overcome the force of the blast they fall success ively into the proper compartments, while the lighter particles driven ahead by the main blast and upward by the lower blast is carried into the dust-chambers, in which it collects. The result is a classified and graded mass of ore of regularly-(leereasing size and weight from the inlet end back to the exit. It is of course unnecessary to supply an upward currentof air to all the chambers of the series. Toward the end of the passage the particles of ore become so light that such an upward current would tend to prevent the successful operation of the machine.

hat I claim is 1. In a machine for grading ore, the combination, with a separating passage divided into open-topped compartments arrai'iged in a series, of an air-blast pipe communicating with said passage above said compartments and a counter-blast pipe below the main blast for supplying air to each of said compartments, substantially as described.

2. In a machine for grading ore, the combination of a separating-passage divided by partitions into a series of open-topped compartments, an air-blast pipe entering said passage at one end and above said compartments, a counter-blast pipe, and branch pipes from said counter-blast pipe extending separately into said compartments, substantially as described and shown.

In a machine forgradingore, and in combination with the divided separating-passage, an air-blast pipe having branch pipes and air-jets in the divisions of said chamber and an adjustable spreader in each air-jet, substantially as described and shown.

4C. In a machine for grading ore, the combination, with the separating-passage having open-topped compartments, of an air-box communicating therewith, a blower for sup plying air to said box, and a blast-pipe leading from said air-box below the separatingassa 'e and haviir branch )i )es entering b h c.

the said compartment, substantially as described and shown.

EDW'ARD L. CRAIG. Witnesses:

L. W. SEELY, J as. l. LANoHoRNn.

IIO 

